I reckon the reason that lt hts tend not to be made of carbon is the type of riding they encourage, ie hooning about in the woods, on rougher terrain, isn't what carbon does very well without the aid of a rear shock to stop all that lovely stiffness from drop kicking you repeatedly in the plums. What attributes of carbon do you want? Light weight? Means the bike won't be that durable (and flexy) on terrain requiring the 160mm fork. Super Stiffness? See above re your plums, and it won't be 'that' light.

IMO you'd have more choice, and a better bike, if you picked a different material. Or if you need carbon, go full sus.

I swapped from an alloy Rock lobster B52 and the Carbon 456 is far more forgiving that that ever was. It is not zingy like steel [ then again it weighs 2 lb less than my steel frame [ to be fair it has an EBB in it]

As for choices it would appear limited but I like my 456 though it gets more rocks than woods

I reckon the reason that lt hts tend not to be made of carbon is the type of riding they encourage, ie hooning about in the woods, on rougher terrain, isn't what carbon does very well without the aid of a rear shock to stop all that lovely stiffness from drop kicking you repeatedly in the plums. What attributes of carbon do you want? Light weight? Means the bike won't be that durable (and flexy) on terrain requiring the 160mm fork. Super Stiffness? See above re your plums, and it won't be 'that' light.

And once again, someone fails to grasp the concept of "Specific Stiffness/Strength"..........

(i.e. Stiffness or Strength per unit of mass).

You can easily make a CF frame less stiff and less strong than a steel one.

It's also worth noting that in order to "absorb" terrain inputs, you'd be talking about a frame that could deflect in the order of INCHES (like a shock/damper) at low frequencies. I'm sure at say >200Hz & 0.1mm a CF frame has a different damping co-efficient than a steel one, but at 1Hz & 25mm it isn't any different!

TBH, the whole "CF frames are stiff and buzzy" is pretty much marketing / reviewer rubbish! Do the maths and that much is obvious.

So, the real reason you don't see too many Cf long travel hardtails is the development costs and hence frame costs. If you're going to all that effort, then most designers are going to include rear suspension in the design whilst they are there. Few people are going to spend say £1500 on a CF hardtail when you could have an Ally FS for the same money (which the general public see as better value for money etc)